Ball joint with a retainer/safety nut that prevents accidental separation of the ball stud and the socket

ABSTRACT

This invention relates in general to ball joints, such as are commonly used in motor vehicle steering and suspension systems (inclusive of upper ball joints, lower ball joints and tie rod ends). The invention is particularly aimed at preventing motor vehicle accidents that are caused by accidental separation of ball joints or tie-rod ends. In particular this invention relates to a ball joint assembly having shafts on both sides of the ball and a socket with openings on both sides to accommodate the two shafts. The main shaft, as is found in standard ball joints, serves the purpose of joining components while the second shaft has a retainer/safety nut, which prevents accidental separation of the ball joint. The retainer nut ensures that the ball cannot come out of the socket in the event of ball and socket wear. The side of the socket that has the retainer nut can be closed by either welding, press-fitting or by way of a cap that is screwed into the socket. For the version with a screw-in cap, the cap can be screwed into the socket towards the ball to eliminate free play. After screwing in the cap, the retainer nut must also be adjusted accordingly. The cap can also be unscrewed and removed for the purpose of renewing the ball joint to replace worn out polymer bearing using pre-molded replacement polymer bearings. Both shafts are protected from dust and natural elements by rubber boots.

BACKGROUND OF THE INVENTION

This invention relates in general to ball joints, such as are commonlyused in vehicular steering and suspension applications to transmit forcebetween a steering mechanism and a steered wheel of a vehicle. Inparticular, this invention is aimed at avoiding accidental separation ofthe ball joint assembly due to wear of both the ball and the socket. Theinvention also allows for renewal of the ball joint by allowing forreplacement of the polymer bearing. The design includes aretainer/safety nut for preventing accidental separation of thecomponents of the ball joint as a result of such wear.

Ball joints are well known structures that are used in a variety ofmechanical linkages. For example, ball joints are commonly used invehicular steering and suspension assemblies to allow front wheels toturn sideways and also to transmit force between a steering mechanismand a steered wheel of a vehicle. A typical ball joint includes a ballstud that is received within a lubricated socket. The ball stud includesa spherically-shaped head portion having an elongated shaft portionextending therefrom. The spherically-shaped head portion of the ballstud is received within and cooperates with a correspondingspherically-shaped recess formed in the socket. This arrangementpositively connects the ball stud to the socket so as to permit someforces to be transmitted therethrough. This arrangement also allows theball stud to pivot in any direction relative to the socket.

It has been found that after a period of use, the cooperating portionsof the ball stud and the socket of the ball joint will experience wear.Such wear can create undesirable looseness between the ball stud and thesocket of the ball joint, resulting in the generation of noise andmisalignment between the ball stud and the socket. In extreme cases,such wear can contribute to or cause the accidental separation of theball stud from the socket, resulting in a total failure of the balljoint. Accidental separation of the ball stud from the socket is commonin areas with bumpy roads. Unfortunately, because the spherically-shapedhead portion of the ball stud is received within the correspondingspherically-shaped recess formed in the socket, it is often difficult todetermine how much wear has occurred within the ball joint withoutremoving the ball joint from its application and disassembling the ballstud and the socket for inspection. Such removal and disassembly is timeconsuming and expensive. In extreme cases, wear of the ball stud fromthe socket can lead to motor vehicle accidents that are caused by theaccidental separation of the ball joints or tie rod ends. Thus, it wouldbe desirable to provide a device that prevents accidental separation ofthe ball joint as a result of such wear. It would also be desirable toprovide a method for renewing the ball joint so as to prolong itsservice life.

DESCRIPTION SUMMARY OF THE INVENTION

This invention relates to a retainer/safety nut that prevents theseparation of the ball stud from the socket as a result of wear of theball stud or socket. The improved ball joint design includes anadditional opening on the socket to accommodate an additional shaft onthe other side of the standard ball stud. The additional shaft hasthreads for fitting of a retainer/safety nut. The retainer/safety nutensures that the ball does not leave the socket. The retainer nut isbell-shaped so as to allow for sideways movement of the shaft. The sideof the socket that has the retainer nut can be closed permanently forexample by welding or press-fitting a cap onto the socket or by way of acap that is screwed into the socket. For the version with a screw-incap, the cap can be screwed into the socket towards the ball toeliminate free play. After screwing in the cap, the retainer nut mustalso be adjusted accordingly. The retainer/safety nut and the whole balljoint assembly are protected from dust and natural elements by rubberboots. Various objects and advantages of this invention will becomeapparent to those skilled in the art from the following detaileddescription of the preferred embodiments, when read in light of theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a ball joint with a retainer/safety nutand a screw-in cap in accordance with this invention.

FIG. 2 is a perspective view of the ball with shafts on either side ofthe ball showing preferred embodiments.

FIG. 3 is a perspective view of a ball joint with a retainer/safety nutand coil spring in accordance with this invention.

FIG. 4 is a perspective view of the tie rod assembly with aretainer/safety nut in accordance with this design.

DESCRIPTIVE KEY (REFER TO FIG. 2)

-   -   1 ball    -   2 Main stud    -   3 auxiliary study for retainer nut    -   4 hole for cotter/safety pin    -   5 hole for cotter/safety pin    -   6 retainer/safety nut    -   7 socket    -   8 polymer bearing    -   9 rubber boot/dust cover    -   10 rubber boot/dust cover    -   11 screw-in cap

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (REFER TO FIG. 2)

-   -   The invention relates to ball joint assembly having a ball (1)        with studs/shafts on both sides of the ball (2 &3). The main        stud/shaft (2) is the same as the stud found in conventional        ball joints. The auxiliary stud (3) is shorter than the main        stud and is for holding the retainer/safety nut that prevents        accidental separation.    -   Both shafts have holes for cotter/safety pins (4&5). The main        shaft (2) holds the castle nut as in conventional ball joints.    -   The retainer nut (6) is bell shaped so as to allow the ball and        studs to move in all directions.    -   The ball (1) and socket (7) function as a typical ball and        socket assembly.    -   A polymer bearing (8) is fitted into the socket. Press fitting        of the ball joint assembly or screwing-in of the socket cap        ensures that the polymer bearing is tightly packed. The polymer        bearing absorbs impact thereby protecting the ball and socket.        It also serves to reduce friction between the ball and socket.    -   When the polymer bearing is worn, some up and down movement in        the ball will result. This movement is a sign of wear and can be        evidenced by a rattling noise coming from the vehicle        suspension. The wear in the ball joint can also be felt by        shaking the wheel up and down.    -   The end of the socket with the retainer nut can either be closed        by way of press-fitting a cap or by way of a screw-in cap (11).        For the version with a screw-in cap, the cap can be screwed into        the socket towards the ball to eliminate free play (see FIGS.        3&4). After screwing in the cap, the retainer nut must also be        adjusted accordingly.    -   The cap can be unscrewed and removed for the purpose of renewing        the ball joint by way of replacing the worn-out polymer bearing        using pre-molded replacement polymer bearings. This prolongs the        service life of the ball joint.    -   The ball and socket are protected on both sides by rubber boots        (9 & 10). The boots are held firmly in place by rings as in        conventional ball joints.    -   As the ball wears, the ball moves in the direction of the main        shaft bringing the retainer nut into contact with the socket,        thereby preventing accidental separation of the ball and socket.    -   A coil spring can be added to this design between the socket and        the retainer/safety nut to reduce impact and vibration which may        result from wear of the ball and socket (see FIG. 3).

The present invention may be used as a substitute for a conventionalball joint or may be installed in new vehicles. The invention may alsobe used in other non-motor vehicle applications that require balljoints. The invention can be used on all-steel ball joint that usegrease for eliminating friction, as well as on low-friction ball jointsthat use polymer bearings. The invention can also be used with loadcarrying and non-load carrying ball joints.

The foregoing descriptions of specific embodiments of the presentinvention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention and method of use to the precise forms disclosed. Obviouslymany modifications and variations are possible in light of the aboveteaching. The embodiment was chosen and described in order to bestexplain the principles of the invention and its practical application,and to thereby enable others skilled in the art to best utilize theinvention and various embodiments with various modifications as aresuited to the particular use contemplated. It is understood that variousomissions or substitutions of equivalents are contemplated ascircumstance may suggest or render expedient, but is intended to coverthe application or implementation without departing from the spirit orscope of the claims of the present invention.

What is claimed is:
 1. A ball joint assembly having studs on both sidesof the ball: a ball adapted to fixedly receive the first component; saidball having an additional shaft portion the ball defining a central axisof symmetry there through, said shaft portion being threaded to receivea V-shaped retainer/safety nut; a nut adapted to allow the ball to movein all directions. Some significant amount of wear in the ball portionand the socket causes the retainer nut to move closer to the socket.Wear also causes some upward and sideways movement in the ball andsocket assembly.
 2. The additional stud described in claim 1 is shorterthan the standard stud and has threads and a hole for the cotter pin forthe bell-shaped retainer nut.
 3. The bell-shaped retainer nut describedin claim 1 allows the shaft to move in all directions up to apredetermined angle that is determined by the openings on both side ofthe socket. The retainer nut ensures that the ball cannot come out ofthe socket in the event of ball and socket wear.
 4. The assembly definedin claim 1 is supported by polymer bearings at the upper and lower endsfor absorbing impact. The polymer bearing also serves as an indicator.Once the polymer bearing wears out, some up and down movement will beevident in the ball assembly.
 5. The retainer nut defined in claim 3 islocked using a cotter pin to ensure that it does not unwind and lead toaccidental separation of the ball joint assembly.
 6. The assemblydefined in claim 1 is protected on both sides from dust and othernatural elements by rubber dust covers. The said covers also containsome grease for keeping the assembly lubricated.
 7. The socket describedin claim 1 has two openings on opposite ends to accommodate the twostuds.
 8. The socket described in claim 1 can be sealed by screwing-inor pressing.
 9. The screw-in type socket can be adjusted for ball andsocket wear by further screwing in the socket cap. The screw in socketcan also be opened and new polymer bearing added in.
 10. The wear of theball and socket can be tested by shaking the vehicle wheel up and down.In accordance with the provisions of the patent statutes, the principleand mode of operation of this invention have been explained andillustrated in its preferred embodiments. However, it must be understoodthat this invention may be practiced otherwise than as specificallyexplained and illustrated without departing from its spirit or scope.